Interval Notation
Interval Notation is a skill on Pengi from Lesson 4: Quadratic Inequalities in Yoshiwara Intermediate Algebra.
Key Concepts
Property An interval is a set that consists of all the real numbers between two numbers $a$ and $b$. 1. The closed interval $[a, b]$ is the set $a \le x \le b$. 2. The open interval $(a, b)$ is the set $a < x < b$. 3. Intervals may also be half open or half closed , like $[a, b)$ which is $a \le x < b$. 4. The infinite interval $[a, \infty)$ is the set $x \ge a$. 5. The infinite interval $( \infty, a]$ is the set $x \le a$. A union of intervals, denoted with $\cup$, combines two or more sets.
Examples The inequality $ 4 \le x < 1$ is written in interval notation as $[ 4, 1)$.
The set of all numbers greater than 5 is written as the infinite interval $(5, \infty)$.
Common Questions
What is Interval Notation?
Interval Notation is a skill on Pengi from Lesson 4: Quadratic Inequalities in Yoshiwara Intermediate Algebra.
What grade level is Interval Notation for?
Interval Notation is part of the Grade 7 Math curriculum, covered in Yoshiwara Intermediate Algebra. It is designed for students studying Math at the Grade 7 level.
How can I learn Interval Notation?
Pengi offers an AI-guided lesson for Interval Notation that walks you through the key concepts step by step. The lesson is aligned to Yoshiwara Intermediate Algebra so the content matches what you see in class.
How do I practice Interval Notation?
After learning the concept, use the Practice mode to work through targeted exercises on Interval Notation. The AI adapts to your level and gives feedback on each answer so you can identify and fix mistakes.
Which textbook covers Interval Notation?
Interval Notation is covered in Yoshiwara Intermediate Algebra, specifically in Chapter 4: Applications of Quadratic Models under Lesson 4: Quadratic Inequalities. Pengi's lesson is aligned directly to this textbook so you can follow along with your class.
Is Interval Notation free to study on Pengi?
Yes, the core Learn and Practice modes for Interval Notation are available for free on Pengi. No credit card is required to start studying.